Cpanel Error – invalid maildirsize file

Today we got a error message in one of our email accounts that “Maildir: quota exceeded”.

I tried increasing Mail quota from 50 MB to 100 MB thru cpanel but we got the following error “Error – invalid maildirsize file”

After investigation we found a solution for this.

We took the following steps to fix this:

1. Login to your server via FTP
2. Navigate to the following path /mail/yourdomain.com/user

Substitute yourdomain.com/username with the correct email domain/user. E.G. user@yourdomain.com

3. From this directory, delete the file named maildirsize
4. Once this file is deleted, the system should reform the mail account automatically with the correct mailbox quota size upon new email activity.

Notes: If the correct mailbox quota is still not being displayed, from within cPanel, you can navigate to email accounts and click the change quota button to set a new quota.

Hope this information will be useful to all.